Microsoft Office is more than a suite of applications.  It's also an important development platform.

A change as big as the new Office 12 user interface has implications for developers.  There are thousands of publicly available add-ins written to take advantage of Office.  Many companies have also written their own suite of internal add-ins which extend Office to impressively integrate into their business systems.

The good news is that Office 12 provides an enormous opportunity for add-in developers.  We've introduced a new model for extending the Office interface code-named RibbonX, which addresses directly many of the toughest issues facing Office UI developers today.  Based on a declarative, XML-based model, RibbonX unlocks much of the power of the new UI in a straightforward way, whether you write in C#, Visual Basic.NET, C++, or VBA.

In an upcoming series of articles, I'll walk you through the extensibility story of the Office 12 UI.  If you are especially interested in these developer issues, I've created a new Developer category (RSS) which you can use to follow just these posts.  (Of course, I'm sure you'd rather keep reading the entire blog, right?)

Getting the programmability story right has been one of the biggest challenges of this release.  Not since perhaps the changeover from Windows 3.1 to Windows 95 has there been such a large number of existing applications expecting a totally different UI from the environment they ended up running in.

Tomorrow, I'll kick off the series by discussing what happens to the existing base of Office add-ins and macros in the new UI.  (Hint: They still work!)